Extensible Counters in Performance Monitor (179456)

SUMMARY

Extensible counters are additions to the base Performance Monitor counters. Programs like SQL and Exchange add extensible counters to Performance Monitor. Custom counters can also be programmatically written and implemented into Performance Monitor. For more information on writing extensible counters, see Windows NT Resource Kit 3.51, Volume 4 chapter 13.

MORE INFORMATION

Extensible counter information is stored in both of the following places:

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\Current Version\Perflib\009
%Systemroot\system32\Perfc009.dat and Perfh009.dat.

NOTE: All extensible counters are listed after number 1846 END MARKER.

The service that loads the extensible counter stores the information in the following location:

HKEY_LOCAL_MACHINE\System\Currentcontrolset\Services\<service name> \Performance

   where <service name> is the name of the service that is loading the
   extensible counters.

Under the Performance key, the significant values are:

FIRST COUNTER: LAST COUNTER: LIBRARY:

FIRST COUNTER:

The entry has a hex value. If we change this hex value to decimal it gives us the location the extensible counters start in the Perfc009.dat file.

NOTE: This value only applies to the service that is loading the counter

LAST COUNTER:

The entry has a hex value. If we change the hex value to decimal it gives the location in the .dat file of the last counter for this service.

LIBRARY:

This entry indicates which .dll file is being used to load the counters.